This contribution is organised in the following manner - the first section is devoted to the development of Proudhon’s thought in relation to speculation. It is divided into two parts. The first part is dedicated to Pierre-Joseph Proudhon’s definitions of stock market speculation or gambling with shares that for him served no purpose either from a human or economic perspective and was therefore condemnable and to be contrasted with entrepreneurial speculation that, even though it is a highly-risky activity, involves the spirit of enterprise and provides the lifeblood of economic growth. The second part allows us to present Pierre-Joseph Proudhon’s.